In the fabrication of semiconductor work pieces or other integrated circuits, two types of semiconductor processing systems are commonly employed. The first type of system which is commonly used relates to a batch processing system. Further, the other type of system which is used is employed with only single semiconductor work pieces. While those skilled in the art have long recognized that single work piece processing systems have many advantages, such as providing uniformity of production, it has many shortcomings as well. Chief among these shortcomings is that it is often difficult to achieve uniform heating between each work piece. Additionally, the processing speeds of such assemblies, coupled with a slow throughput and high overhead operating costs, are typically severe limitations which have detracted from the widespread adoption and use of such assemblies.
In the prior art batch processing systems which have been used, heretofore, semiconductor work pieces are typically placed either in a horizontal or vertical orientation relative to a carrier and are then placed in a processing chamber for appropriate processing. For example, in U.S. Pat. No. 5,855,681, several batch processing apparatuses for semiconductor work pieces are shown and described and which have a polygonal or round processing chamber containing multiple work stations, each work station holds one semiconductor work piece. The teachings of this patent are incorporated by reference, herein.
To ensure uniformity of production, it is well known that the processing conditions for each of the semiconductor work pieces needs to be substantially identical. Batch processing systems utilized, heretofore, have been designed in a fashion whereby each of the processing stations share many of the same pieces of equipment and resources provided by the apparatus. For example, such batch processing systems commonly have a common heating apparatus; gas source; inlet/exhaust apparatus; plasma generators and the like. It has been found that this shared arrangement of various assemblies inevitably causes non-uniform processing of the semiconductor work pieces. As should be understood, in the processing of semiconductor work pieces employing plasma having active particles which are energized by RF energy, the manufacturing procedure for the deposition or etching of a semiconductor work piece to gain uniformity in production is considered much more rigorous. Heretofore, to achieve uniformity of production utilizing plasma processing, much research activity has been directed towards controlling the gas pressure and the inputted RF energy. While controlling the uniformity of the RF energy input is a relatively easy task, achieving uniformity of gas pressure inside a processing chamber has proven to be more difficult endeavor.
In this regard, to achieve uniformity of gas pressure inside a plasma processing chamber, two solutions have been employed. The first solution has been to isolate the processing stations in the processing chamber. When this approach is used, the manufacture of the chamber becomes a more difficult task inasmuch as the respective processing stations must be as structurally identical as possible. Still further, the respective gas and electric input devices similarly need to be as closely similar or substantially identical. However, and as will be readily recognized, due to machining errors which inevitably occur in the fabrication of the processing chamber, or further, as wear and tear on the machine occurs, different processing conditions between the respective processing stations begin to emerge.
Therefore, it should be clear that this approach can hardly insure strict uniformity of the resulting plasma processing of the semiconductor work pieces in the same batch. Another prior art measure which has been employed from time-to-time is to couple the respective processing stations in fluid flowing relation one relative to the other. In this arrangement, the gas pressure between the respective processing stations can be maintained and the distribution of neutral particles within the plasma is maintained. However, because the processing chamber is not sealed, charged particles will often be shared between the processing regions and interfere with each other. This sharing of charged particles has the effect of disturbing the electrical fields in the respective processing stations and thus deteriorates the uniformity of the resulting semiconductor work pieces provided by the respective plasma processing chambers.
Therefore, a plasma processing apparatus which avoids the shortcomings attendant with the prior art apparatus and methodology utilized heretofore is the subject matter of the present application.